Effect of Plantago major on cough severity in acute bronchitis: A double-blind randomized clinical trial.

Background: Treatments for acute bronchitis is usually a supportive care to relieve upper respiratory symptoms. This study aimed to evaluate the effect of Plantago major syrup (PMS) on cough severity in acute bronchitis.

Methods: Patients (20-75 years-old) referred to the clinic of infectious diseases in Ayatollah Rouhani Hospital, Babol, Iran with a complaint of cough and the Bronchitis Severity Scale (BSS) ≥5 entered the study. The patients randomly received PMS or placebo 30 ml/day for 10 days. Patients were visited before treatment and on days 5 and 10 after treatment. The primary outcome was BSS score and secondary outcome was the life quality that was measured by means of the Persian version of the Leicester Cough Questionnaire (LCQ) at the first visit and on the 10^th day.

Results: Of the 121 patients diagnosed with acute bronchitis, 80 eligible patients (42.87±11.75 years-old) were randomly divided into PMS and placebo groups. The BSS score in the PMS group after 10 days was significantly lower than that of the placebo group (P=0.001). Frequency of cough (P=0.001), sputum production (P=0.005), and chest wall pain (P=0.008) were significantly lower in the PMS group than in the placebo group. In terms of quality of life, all items, including psychological, physical, and social domains, as well as total scores, were altered significantly in the PMS group compared to placebo. During monitoring of side effects, no significant adverse effects were stated in either group.

Conclusion: The study indicates the palliative effects of PMS in relieving the symptoms of acute bronchitis and improving quality of life.